Self-propelled working machine

ABSTRACT

Protective projections ( 26 D) which are provided on cylinder mounting brackets ( 26 ) of a cargo handling tool ( 21 ) are arranged to project toward a vehicle body ( 2 ) from behind the cargo handling tool ( 21 ). When the vehicle body ( 2 ) is driven in reverse direction with a boom ( 12 ) in a folded position on the side of the ground, the protective projections ( 26 D) are collided against obstacles (A) on the ground prior to a rod ( 27 C) of a fork cylinder ( 27 ) if the lower side ( 2 A) of the vehicle body ( 2 ) has passed over and clear of the obstacles (A). Thus, the protective projections ( 26 D) function to protect the fork cylinder rod ( 27 C) of the fork cylinder ( 27 ) against direct collision against obstacles (A) on the ground.

TECHNICAL FIELD

This invention relates to an automotive working machine, for example,which is provided with an automotive vehicle like a lift truck.

BACKGROUND ART

Generally, lift trucks are well known as an automotive working machinewhich is resorted to freight shipping (cargo handling) jobs from groundto higher position. The lift trucks of this sort are largely constitutedby an automotive vehicle body provided of front and rear wheels, a boomliftably provided on the vehicle body for derricking motions, a workingtool like a cargo handling tool rotatably supported at a fore end of theboom, and a tool operating cylinder located between the cargo handlingtool and the boom for turning the cargo handling tool in upward anddownward directions relative to the boom (e.g., as known from JapanesePatent 2,559,831 and International Publication WO 89/00972).

In the case of a lift truck of this sort, the boom is lowered into aflatly folded position on the side of the ground at the time of loadingfreight goods onto a fork of the cargo handling tool, and then turnedupward to lift and transfer the freight goods to a higher level from theground. At this time, the tool operating cylinder which is providedbetween the boom and the working tool functions to turn the cargohandling tool according to the elevation angle of the boom to maintainthe fork of the cargo handling tool constantly in a horizontal posturefor transferring the freight goods in a stabilized state.

By the way, the tool operating cylinder which is used on theabove-described lift truck is normally constituted by a tube which isattached to the boom on the side of its bottom end, a piston which isslidably fitted in the tube, and a rod which is attached to the pistonat its base end and connected to a cargo handling tool at its fore endwhich is projected out of the tube. When the boom is lowered into aflatly folded position on the side of the ground, the fore end of thetool operating cylinder is projected downward toward the ground surfacefrom the lower side of the vehicle body.

Therefore, when the vehicle is on a rocky ground and driven in reversedirection with the boom in the flatly folded position, it is very likelyfor the rod of the working cylinder which is projected downward from thelower side of the vehicle body to be directly collided against a rock orsimilar obstacle on the ground surface even if the lower side of thevehicle has passed clear of the rock. The collision against such a rockcan result in fracture of the working cylinder.

On the other hand, as to other automotive working machines by the priorart, there has been known a hydraulic excavator which is provided withan excavating bucket along with a bucket operating hydraulic cylinder,and in which a tubular or pipe-like cover is employed as a protector andarranged to enshroud a rod portion which is projected out of a tube ofthe hydraulic cylinder (e.g., as known from Japanese Patent Laid-OpenNo. 2001-82414).

The protector cover in the just-mentioned prior art is a tubular shapeand larger in diameter than the hydraulic cylinder tube. Onelongitudinal end of the cover tube is attached to the fore end of therod which is projected out of the hydraulic cylinder tube. Accordingly,the outer peripheral side of the hydraulic cylinder rod is constantlyenclosed in the cover tube to prevent collisions of sand and soilagainst the hydraulic cylinder rod.

However, in the case of the prior art cover tube for a hydrauliccylinder, as mentioned above, one longitudinal end of the cover tube isattached to the fore end of the hydraulic cylinder rod. Therefore, whensand and soil comes into colliding contact with the cover tube, theimpacts of collision are transmitted to the hydraulic cylinder rod tocause deformations and damages to the rod.

Further, in the case of the cover tube just mentioned, the cover isformed in a tubular shape to enclose the hydraulic cylinder tube and rodfrom the outer peripheral side thereof. Therefore, sand and soil tend todeposit between the cover and the hydraulic cylinder rod to hampersmooth operations of the hydraulic cylinder.

DISCLOSURE OF THE INVENTION

In view of the above-mentioned problems with the prior art, it is anobject of the present invention to provide an automotive working machinewhich is provided with a means for protecting a tool operating cylinderfrom collision against obstacles on the ground surface to ensure smoothoperations of the cylinder over an extended period of time.

According to the present invention, in order to solve theabove-mentioned problems, there is provided an automotive workingmachine having an automotive vehicle body provided in left and rightfornt wheels and left and right rear wheels, a boom liftably mounted onthe vehicle body, a working tool rotatably supported on a fore endportion of the boom, and a tool operating cylinder located between theboom and the working tool at one and the other axial end thereof to turnthe working tool in upward and downward directions relative to the boom.

The automotive working machine according to the present invention ischaracterized by the provision of: a tool mounting member provided onthe back side of the working tool, on the side of the vehicle body, andhaving a boom connecting portion pivotally connected to the fore endportion of the boom, along with a cylinder mounting member having acylinder connecting portion to be pivotally connected to the other endof the tool operating cylinder; and protective projections provided onthe cylinder mounting member and projected from back side of the workingtool toward the vehicle body to protect the other end of the tooloperating cylinder from obstacles on ground surfaces when the vehiclebody is driven in reverse direction with the boom in a flatly foldedposition on the side of the ground.

With the arrangements just described, the protective projections whichare provided on the cylinder mounting member of the working tool arebrought into collision against obstacles on ground surfaces prior to thetool operating cylinder when the lower side of the vehicle body passesover and clear of the obstacles during a drive in reverse direction withthe boom in the folded position on the side of the ground. Accordingly,the other end of the tool operating cylinder is prevented and protectedfrom direct collisions against obstacles on the ground surface. Besides,since the protective projections are provided on the cylinder mountingmember of the working tool, impacts of collisions are sustained by theworking tool, preventing the tool operating cylinder from being damagedby impacts of collision.

According to a preferred form of the present invention, top ends of theprotective projections are located at a lower level than a height of alower side of the vehicle body from a ground surface when said boom islocated a folded position on the side of the ground. In this case, whenthe vehicle body is driven in reverse direction with the boom folded tothe ground side, the tool operating cylinder may come into collisionagainst obstacles which are lower than the height of the lower side ofthe vehicle body from a ground surface. Accordingly, it suffices to settop ends of the protective projections at a level which is lower thanthe height of the lower side of the vehicle body from the groundsurface. Namely, the tool operating cylinder can be securely protectedfrom obstacles on the ground without using unnecessarily largeprotective projections.

According to another preferred form of the present invention, theprotective projections are bent in an obliquely upward direction from acylinder connecting portion of the cylinder mounting member toward thetool operating cylinder. In this case, as the working tool is turned inan upward or downward direction about the boom connecting portion of theboom mounting member, the protective projections are kept out ofinterference with the tool operating cylinder to ensure smoothoperations of the working tool.

According to still another preferred form of the invention, theprotective projections are each in the form of an arcuate projectionextending toward the tool operating cylinder and bent arcuately about aboom connecting portion of the boom mounting member at the back of theworking tool.

With the arrangements just described, as the tool operating cylinder iscontracted to turn the working tool upward and downward directions aboutthe boom connecting portion of the boom mounting member, the protectiveprojections are turned arcuately toward the tool operating cylinder insuch a way as to preclude possibilities of interference with theprotective projections.

According to another feature of the present invention, the protectiveprojections are formed separately from the cylinder mounting member anddetachably attached to the cylinder mounting member. In this case, evenif the protective projection or projections are damaged by collisionagainst an obstacle, fresh protective projections can be attached to thecylinder mounting member in place of the damaged ones. Thus, the rod ofthe tool operating cylinder can be protected over an extended period oftime.

According to a further feature of the present invention, the protectiveprojections are constituted by a pair of right and left plate-likemembers adapted to grip the other end of the tool operating cylindertherebetween. In this case, the other end of the tool operating cylinderis gripped by a pair of plate-like protective projections, precludingdeposition of sand and soil between the other end of the tool operatingcylinder and the protective projections to ensure smooth operation ofthe tool operating cylinder.

According to another feature of the present invention, the tooloperating cylinder is constituted by a tube having one axial end thereofconnected to the boom, a piston slidably fitted in the tube, and a rodhaving one axial end thereof connected to the piston and projected outof the tube at the other axial end connected to the cylinder connectingportion of the cylinder mounting member; the protective projectionsbeing adapted to protect the other projected end of the rod.

With the arrangements just described, for example, when the vehicle bodyis driven in reverse direction with the boom in a folded position on theside of the ground despite existence of obstacles on the ground surface,the rod of the tool operating cylinder is prevented and protected fromcollision against the obstacles on the ground.

In a further preferred form of the present invention, the boom isprovided with an outer boom of a hollow tubular shape being liftablyconnected to the vehicle body at a base end portion, and an inner boombeing extensibly fitted in the outer boom and provided with a cylindermounting member on a fore end portion thereof, and further comprises aboom cylinder being located outside the outer boom and having a base endportion thereof attached to the outer boom and a fore end portionsupported on a cylinder mounting portion on the inner boom, the outerboom being provided with an opening in a fore end portion to accommodatethe cylinder mounting portion in a retracted position inward of a foreend of the outer boom when the inner boom is retracted into the outerboom.

With the arrangements just described, when the inner boom is retractedinto the outer boom, the cylinder mounting portion which is provided ona fore end portion of the inner boom can be accommodated in the openingwhich is provided in a fore end portion of the outer boom and retainedin a position which is retracted behind the fore end of the outer boom.Accordingly, in addition to the protection of the tool operatingcylinder by the protective projections, it becomes possible to minimizethe distance between the fore end of the outer boom and the fore end ofthe retracted inner boom, that is to say, to minimize the length of theboom as a whole in the contracted state.

Further, in a further preferred form of the present invention, the outerboom is composed of a tubular body for accommodating the inner boom, anda box-like frame body securely attached to a fore end of the tubularbody, the frame body defining therein said opening in a correspondingposition relative to the cylinder mounting portion of said inner boom.In this case, when the inner boom is retracted into the outer boom, thecylinder mounting portion on the inner boom can be withdrawn into theopening of the frame body to minimize the entire length of the boom inthe contracted state.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a front view of a lift truck incorporating a first embodimentof the present invention;

FIG. 2 is a front view showing on an enlarged scale of a boom, cargohandling tool, fork cylinder and protective projection in FIG. 1;

FIG. 3 is a left-hand side view of the boom, cargo handling tool andfork cylinder, taken in the direction of arrows III—III in FIG. 2;

FIG. 4 is a solitary perspective view of the cargo handling toolaccording to the first embodiment of the present invention;

FIG. 5 is a vertical sectional view taken in the direction of arrows V—Vof FIG. 3, showing on an enlarged scale the boom head, cargo handlingtool, fork cylinder and protective projection in an operational phasewhen the rod of the fork cylinder is extended out;

FIG. 6 is a vertical sectional view similar to FIG. 5 but showing theboom head, cargo handling tool, fork cylinder and protective projectionin an operational phase when the rod of the fork cylinder is contracted;

FIG. 7 is an exploded perspective view of the cargo handling tool andprotective projection plate according to a second embodiment of thepresent invention;

FIG. 8 is a front view of a working mechanism adopted by a thirdembodiment of the present invention, showing the working mechanism inrelation with the boom which is in a contracted state;

FIG. 9 is a vertical sectional view of the working mechanism in thethird embodiment of the invention;

FIG. 10 is a perspective view of a fore end side of a first step boommember;

FIG. 11 is a front view of the working mechanism of the third embodimentof the invention, showing the working mechanism in relation with theboom which is in an extended state;

FIG. 12 is a vertical sectional view similar to FIG. 5 but showing theboom head, cargo handling tool, fork cylinder and protective projectionaccording to a fourth embodiment of the invention;

FIG. 13 is a perspective view of the cargo handling tool adopted by thefourth embodiment; and

FIG. 14 is a vertical sectional view similar to FIG. 5 but showing amodification of the protective projection.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereafter, with reference to FIGS. 1 through 12, the automotive workingmachine according to the present invention is described moreparticularly by way of its preferred embodiments which are applied to alift truck.

Referring first to FIGS. 1 to 6, there is shown a first embodiment ofthe present invention. In these figures, indicated at 1 is a lift truckwhich is largely constituted by a wheel type automotive vehicle body 2,and a working mechanism 11 which will be described in greater detailhearinafter. The lift truck 1 is used for cargo handling jobs, drivingthe vehicle body 2 while lifting up freight goods from the ground andtransferring same to an elevated place by the working mechanism.

In this instance, the vehicle body 2 is largely constituted by a frame 3which is formed of thick steel plates and extended toward front and rearsides of the vehicle body, drive sources such as engine, hydraulic pump,hydraulic motor and the like (none of which are shown in the drawings)which are mounted on the frame 3, and a cab 6 which will be describedhereinafter. Right and left front wheels 4 (of which the left frontwheel alone is shown in the drawings) are provided in a front side ofthe frame 3, and right and left rear wheels 5 (of which the left rearwheel alone is shown in the drawings) are provided in a rear side of theframe 3.

The right and left front wheels 4 and the right and left rear wheels 5are rotationally driven from a hydraulic motor (not shown)simultaneously. That is to say, the vehicle body 2 is driven in aforward direction as indicated by an arrow F or in a reverse directionas indicated by an arrow R by a 4-wheel drive system. The lower side 2Aof the vehicle body 2 (or the lower side 3A of the frame 3) is at apredetermined height H from the ground surface, permitting the vehiclebody 2 to pass over rocks, stones or other obstacles A which are lowerthan the height H.

Indicated at 6 is a cab which is mounted at a longitudinally centerposition on the frame 3 between the front wheels 4 and the rear wheels 5to define an operating room for the machine. Provided internally of thecab 6 are an operator's seat to be taken by an operator, a steeringsystem for the front and rear wheels 4 and 5 and control levers (none ofwhich are shown in the drawings) to be manipulated by an operator incontrolling operations of a working mechanism 11, which will bedescribed in greater detail hearinafter.

Further, right and left outriggers 7 (of which the left outrigger aloneis shown in the drawings) are provided at the front end of the frame 3on the front side of the front wheels 4. Footing plates 7A of theseoutriggers 7 are turned up away from the ground surface when the vehiclebody 2 is put in travel, and for stabilization of the vehicle body 2,the footing plates 7A are set on the ground during a cargo handlingoperation by the working mechanism 11.

Indicated at 11 is the working mechanism which is liftably mounted onthe vehicle body 2 for derricking operations. The working mechanism 11includes a boom 12, a boom lifting cylinder 18, a first step boomcylinder 19, a cargo handling tool 21, and a fork cylinder 27, whichwill be described hereinafter, for lifting and transferring goods whichare loaded on the cargo handling tool 21.

Denoted at 12 is a boom of the working mechanism 11. This boom 12 is ofa telescopic multi-step boom, which is composed of a first step (step-1)boom 13 of a square tubular shape, a second step (step-2) boom 14similarly of a square tubular shape telescopically fitted in the boom ofthe first step boom 13, and a third step (step-3) boom 15 similarly of asquare tubular shape telescopically fitted in the second step boom 14, aboom head 16 fixedly provided at the fore distal end of the third stepboom 15. The base end of the first step boom 13 is pivotally attached toa rear end portion of the frame 3 of the vehicle body 2 by a pin 17.

In this instance, as shown in FIGS. 3 and 5, the boom head 16 is formedin a hollow box-like structure which is enclosed by front and rearplates 16A and 16B and right and left side plates 16C, and extended inan obliquely downward direction from the third step boom 15. A tubularboss portion 16D is provided at the fore end of the boom head 16 forattaching a boom mounting plate 24 of a cargo handling tool 21 whichwill be described in greater detail hereinafter. A bracket 16E isprovided within the boom head 16 for mounting a tube 27A of a forkcylinder 27 which will be described hereinafter. An opening 16F isformed in the rear plate 16B of the boom head 16 for passing andprojecting to the outside a rod 27C of the fork cylinder 27 to theoutside of the boom head 16 which will be described later on.

Designated at 18 is a boom lifting cylinder which is located between thefirst step boom 13 and the frame 3 of the vehicle body 2. This boomlifting cylinder 18 is constituted by a tube 18A which is pivotallyconnected to the frame 3 through a joint pin on the bottom side thereof,a piston (not shown) which is slidably fitted in the tube 18A, and a rod18B which is fixedly connected to the piston at its base end andpivotally connected through a joint pin to a longitudinally intermediateportion of the first step boom 13. By contracting and expanding the rod18B relative to the tube 18A of the boom lifting cylinder 18, the boom12 is turned about the pin 17 to take either a lowered position on theside of the ground surface (the position indicated by solid line inFIG. 1) or a raised or uplifted position away from the ground surface(the position indicated by two-dot chain line in FIG. 1).

Indicated at 19 is a first step boom cylinder which is located betweenthe first step boom 13 and the second step boom 14. The first step boomcylinder 19 is constituted by a tube 19A which is pivotally connected onthe bottom side to a rear end portion of the first step boom 13 througha joint pin, a piston (now shown) which is slidably fitted in the tube19A, and a rod 19B which is fixedly connected at its base end to thepiston and pivotally connected at the fore end to a fore end portion ofthe second step boom 14 through a joint pin. By contracting andexpanding the rod 19B relative to the tube 19A of the first step boomcylinder 19, the second step boom 14 is contracted and expanded relativeto the first step boom 13.

Further, a second step boom cylinder (not shown) is located between thesecond step boom 14 and the third step boom 15. In synchronism with theoperation of the first step boom cylinder 19 contracting or expandingthe second step boom 14 relative to the first step boom 13, the secondstep boom cylinder contracts or extends the third step boom 15 relativeto the second step boom 14. Therefore, simultaneously with the firststep boom cylinder 19, pressure oil is fed to and from the second stepboom cylinder.

Indicated at 21 is a cargo handling tool as a working tool which isgenerally called “an attachment”. The cargo handling tool 21 ispivotally supported at the fore end of the boom 12 (on the boom head 16)through a pin 25, for upward and downward turning movements. In thisinstance, as shown in FIGS. 3 to 5, the cargo handling tool 21 isconstituted by a frame body 22, fork 23, boom mounting plate 24 andcylinder mounting brackets 26, which will be described hereinafter.

Indicated at 22 is a rectangular frame body constituting a base for thecargo handling tool 21. This frame body 22 is largely constituted byright and left side plates 22A which are located at the right and leftsides and faced toward each other, an upper beam 22B of a rectangularshape in section bridged between the right and left side plates 22A, alower beam 22C of a trapezoidal shape in section bridged between theright and left side plates 22A at a lower level than the upper beam 22B,and a rod-like intermediate beam 22D bridged between the right and leftside plates 22A at an intermediate level between the upper and lowerbeams 22B and 22C.

Denoted at 23 are right and left forks which are provided on the frontside of the frame body 22. Each one of the forks 23 is formed, forexample, by bending a thick steel plate into the shape of letter “L”.Each fork 23 is securely fixed to the intermediate beam 22D of the framebody 22 at its upper end. The lower end of each fork 23 is eitherabutted on or securely fixed to the lower beam 22C of the frame body 22.Further, at the lower end, each fork 23 is provided with a cargo loadingsurface 23A which is projected forward from the lower beam 22C of theframe body 22 to load a cargo of freight goods thereon.

Indicated at 24 are boom mounting plates as a boom mounting member, thatis to say, right and left boom mounting plates which are provided on theback side of the frame body 22, in other words, on that side of theframe body 22 which faces toward the vehicle body 2. In this instance,each one of the boom mounting plates 24 is formed, for example,substantially in a triangular shape by the use of a thick steel plate,and securely fixed to the upper and lower beams 22B and 22C of the framebody 22 at its upper and lower ends, respectively. Further, each boommounting plate 24 is provided with a rearwardly bulged portion 24A at anintermediate portion between its upper and lower ends, and a pinreceiving hole 24B is provided in the bulged portion 24A to receive apin 25 which will be described hereinafter. Through the pin 25, thecargo handling tool is pivotally connected to a fore end portion of theboom head 16.

For attaching the cargo handling tool 21 on the boom head 16, the bossportion 16D of the boom head 16 is embraced between the right and leftbulged portions 24A of the right and left boom mounting plates 24, and apin 25 is inserted into and placed in position within the boss portion16D through the pin receiving holes 24B in the boom mounting plates 24.By so doing, the cargo handling tool 21 is pivotally connected to a foreend portion of the boom 12 for up and down turning motions about the pin25. Thus, the pin 25 constitutes pivotal joint means along with the pinreceiving holes 24B in the boom mounting plates 24 of the cargo handlingtool 21 and the boss portion 16D on the part of the boom head 16.

Indicated at 26 are right and left cylinder mounting brackets which areprovided on the back side of the frame body 22 between the right andleft boom mounting plates 24 as a cylinder mounting member. In thisinstance, each cylinder mounting bracket 26 is formed substantially inthe shape of letter “J” by the use of a thick steel plate, and providedwith a vertical plate portion 26A which is extended in the verticaldirection and securely fixed to the upper and lower beams 22B and 22C ofthe frame body 22 on the upper and lower sides, respectively, a footportion 26B which is located at a lower level than the pin receivingholes 24B in the boom mounting plates 24 and extended substantially in ahorizontal direction toward the vehicle body 2 from the lower end of thevertical plate portion 26A, and a pin receiving hole 26C which is formedin the foot portion 26B as a cylinder connecting portion.

In this instance, the pin receiving hole 26C is provided in a part ofthe foot portion 26B which is located at a lower level and at a closerposition to the vehicle body 2 than the pin receiving holes 24B in theboom mounting plates 24. An end of a fork cylinder 27 is pivotallyconnected to the pin receiving holes 26C through a pin 29 which will bedescribed hereinafter. Further, protective projections 26D areintegrally provided at the toe ends of the respective foot portions 26Bfurther than the pin receiving hole 26C, as described in greater detailhereinafter.

Indicated at 27 is a fork cylinder which is provided between the framebody 22 of the cargo handling tool 21 and the boom head 16 of the boom12 as a working cylinder. By this fork cylinder 27, the cargo handlingtool 21 is turned up and down relative to the boom 12. In this instance,as shown in FIG. 5, the fork cylinder 27 is constituted by a tube 27Awhich is located within the boom head 16, a piston 27B which is slidablyfitted in the tube 27A, and a rod 27C which is attached to the piston27B at its one axial end and projected out of the tube 27A at the otheraxial end.

The bottom side of the tube 27A, at one axial end of the fork cylinder27, is pivotally supported on the brackets 16E in the boom head 16through a pin 28. On the other hand, the rod 27C, at the other axial endof the fork cylinder 27, is projected out of the boom head 16 throughthe opening 16F. The rod 27C is provided with a boss portion 27D at itsend portion. The boss portion 27D is interposed between the foot portion26B of the right and left cylinder mounting brackets 26 and pivotallyconnected to said bracket 26 by means of a pin 29 which is inserted inthe pin receiving holes 26C of the cylinder mounting brackets 26.Therefore, the rod 27C of the fork cylinder 27 is pivotally connected tothe cargo handling tool 21 by the pin 29. Thus, the pin 29 constitutes apivotal connection means between the pin receiving holes 26C in thecylinder mounting brackets 26 and the rod 27C of the fork cylinder 27.

Thus, by expanding and contracting the rod 27C of the fork cylinder 27,the cargo handling tool 21 can be turned up and down about the pin 25relative to the boom 12 (relative to the boom head 16) as shown in FIGS.5 and 6. As the boom 12 is elevated from the folded or lowered position,which is indicated by solid line in FIG. 1, to the lifted positionindicated by two-dot chain line, the cargo handling tool 21 is turnedaccording to an elevation angle of the boom 12 to maintain the cargoloading surfaces 23A of the forks 23 constantly in a horizontal posturefor uplifting and transferring freight goods on the cargo loadingsurfaces 23A from a ground level to an elevated place.

Indicated at 26D are protective projections which are provided at thetoe ends of the right and left cylinder mounting brackets 26. Theseprotective projections 26D are integrally formed at the fore ends of thefoot portion 26B of the cylinder mounting brackets 26, which are locatedat a lower level than the pin-receiving holes 24B in the boom mountingplates 24. In this instance, the protective projections 26D areconstituted by a pair of right and left upturned plate-like memberswhich are arranged to grip a fore end portion of the rod 27C of the forkcylinder 27 from opposite sides. More specifically, the protectiveprojections 26D are bent on an obliquely upward direction toward thefork cylinder 27 and projected toward the vehicle body 2 from rear sideof the pin receiving holes 26C in the foot portion 26B of the cylindermounting brackets 26. As seen in FIGS. 1 and 2, when the vehicle body 2is driven in the reverse direction R with the boom 12 folded in thelowered position on the ground side, and is passing over obstacles A onthe ground which the lower side 2A of the vehicle body 2 can clear butthe rod 27C of the fork cylinder 27 cannot, the protective projections26D are brought into collision against the obstacles A prior to the forkcylinder rod 27C to protect same.

In this connection, as shown in FIG. 2, when the boom 12 is folded inthe lowered position on the side of the ground, the protectiveprojections 26D are arranged such that the height h of the top ends ofthe protective projections 26D from the ground surface is lower than theheight H of the lower side 2A of the vehicle body 2 by Δh. In thisinstance, when the vehicle body 2 is driven in the reverse directionwith the boom 12 folded on the side of the ground, the obstacles Ahaving possibilities of collision against the fork cylinder rod 27C ofthe fork cylinder 27 are considered to be lower than the height H of thelower side 2A of the vehicle body 2 from the ground surface.Accordingly, the protective projections 26D can be suppressed to aminimal necessary size by setting the height h of the protectiveprojections 26D from the ground surface at a value smaller than theheight H of the lower side 2A of the vehicle body 2 from the groundsurface.

Further, as shown in FIG. 5, the protective projections 26D are eachformed as an arcuate projection which is projected toward the forkcylinder rod 27C of the fork cylinder 27 arcuately about the pin 25 inthe pin receiving holes 24B in the boom mounting plates 24 of the cargohandling tool 21. Consequently, when the rod 27C of the fork cylinder 27is contracted into the tube 27A as shown in FIG. 6, turning upward anddownward the cargo handling tool 21 about the pin 25, the protectiveprojections 26D are moved toward the fork cylinder rod 27C by an arcuateturn about the pin 25. Thus, the protective projections 26D are arrangedto preclude possibilities of interference with the tube 27A of the forkcylinder 27.

Following are features in operation of the lift truck 1 of the presentembodiment which is arranged in the manner as described above.

Firstly, for a cargo handling operation by the working mechanism 11,freight goods (not shown) are put on the cargo loading surfaces 23A ofthe forks 23 of the cargo handling tool 21, with the boom 12 folded inthe lowered position on the side of the ground as shown in FIG. 1. Then,after driving the automotive vehicle body 2 to a working site, thefooting plates 7A of the outriggers 7 are set on the ground to stabilizethe vehicle body 2.

In the next place, through manipulation of control levers (not shown) ofthe working mechanism 11 by an operator within the cab 6, pressure oilis fed to and from the boom lifting cylinder 18, the first step boomcylinder 19, the second step boom cylinder (not shown) by a hydraulicpump (not shown). By so doing, the boom 12 is raised from the foldedposition (indicated by solid line in FIG. 1) to the elevated position(indicated by two-dot chain line in FIG. 1 by the boom lifting cylinder18). Further, the second step boom 14 and the third step boom 15 areextended out from the first step boom 13 of the boom 12 by the firststep boom cylinder 19 and the second step boom cylinder, respectively.

At this time, in step with the operation of the boom lifting cylinder18, the fork cylinder 27 is put in operation to turn the cargo handlingtool 21 upward or downward relative to the boom head 16 according to theangle of elevation of the boom 12. As a consequence, the cargo loadingsurfaces 23A of the forks 23 can be maintained in a substantiallyhorizontal posture constantly according to the elevation angle of theboom 12, permitting to lift and transfer the freight goods on the cargoloading surfaces 23A from a ground level to an elevated level in astabilized state.

In this instance, when the boom 12 is in the folded position on the sideof the ground, the fore end of the rod 27C of the fork cylinder 27 isprojected downward beyond the lower side 2A of the vehicle body 2 asseen in FIGS. 1 and 2. Therefore, if in this state the vehicle body 2 isdriven in the reverse direction and the lower side 2A of the vehiclebody 2 past obstacles A on the ground, it is very likely for theobstacles A to come into collision against the rod 27C of the forkcylinder 27.

However, in the case of the lift truck 1 according to the presentembodiment, the protective projection 26D is provided on each one of thecylinder mounting brackets 26 of the cargo handling tool 21. Theseprotective projections 26D are provided at the toe ends of the footportion 26B which are located at a lower level than the pin receivingholes 24B in the boom mounting plates 24, and projected toward thevehicle body 2 beyond the pin receiving holes 26C. Therefore, when thevehicle body 2 is driven in the reverse direction as described above,the protective projections 26D are collided against obstacles A on theground prior to the rod 27C of the fork cylinder 27 after the lower side2A of the vehicle body 2 has passed clear of the obstacles A. Thus, forprotective purposes, the protective projections 26D prevent directcollisions of the fork cylinder rod 27C of the fork cylinder 27 againstobstacles A on the ground and protect the fork cylinder rod 27C rightly.

In this case, since the protective projections 26D are provided on thecylinder mounting brackets 26 of the cargo handling tool 21, the impactswhich result from collision of the protective projections 26D by theobstacles A can be sustained by the entire cargo handling tool 21. Itfollows that, in contrast to the afore-mentioned prior art constructionusing a cover around a cylinder rod, the protective projections 26Dfunction to prevent the impacts of collision by the obstacles A frombeing directly transmitted to the fork cylinder 27, that is to say, toprevent damages to the fork cylinder 27 for the purpose of enhancingoperational reliability of the fork cylinder 27.

Further, the paired protective projections 26D are arranged to embrace afore end portion of the fork cylinder rod 27C from opposite sides.Therefore, as compared with the afore-mentioned prior art using atubular cover which is arranged to circumvent the outer peripheral sideof a rod, there is no possibility of accumulation of sand and soilbetween each protective projections 26D and the rod 27C. That is to say,smooth operations of the fork cylinder 27 can be guaranteed over anextended period of time.

Here, obstacles A which would collide against the fork cylinder rod 27Cof the fork cylinder 27 are considered to be lower than the height H ofthe lower side 2A of the vehicle body 2 from the ground surface.Therefore, according to the present embodiment, the protectiveprojections 26D are set at a height h which is smaller than the height Hby Δh, precluding provision of protective projections 26D of suchunnecessarily large sizes as would spread the freedom of structuraldesigns around the protective projections 26D.

Furthermore, according to the present embodiment, each one of theprotective projections 26D is in the form of an arcuate projection whichis extended toward the rod 27C of the fork cylinder 27 arcuately aboutthe pin 25 which is inserted as a joint pin in the pin receiving holes24B in the boom mounting plates 24 of the cargo handling tool 21 and inthe boss portion 16D of the boom head 16. Therefore, while the boom 12is elevated to the uplifted position, the rod 27C of the fork cylinder27 is contracted into the tube 27A in relation with the elevation angleof the boom 12 as shown in FIG. 6, and even when the cargo handling tool21 is turned about the pin 25, there is no possibility of interferenceof the protective projection 26D with the tube 27A of the fork cylinder27. Accordingly, despite the provision of the protective projections26D, the cargo handling tool 21 can be smoothly turned relative to theboom head 16 to maintain the cargo loading surfaces 23A of the forks 23constantly in a horizontal posture according to the angle of elevationof the boom 12.

Moreover, for example, when the boom 12 is in the folded position on theside of the ground (in the position shown in FIG. 2) and the rod 27C ofthe fork cylinder 27 is expanded to turn the cargo handling tool 21, topends of the protective projections 26D are turned about the pin 25 andprevented from colliding against the ground surface in a secure manner.

Now, turning to FIG. 7, there is shown a second embodiment of thepresent invention. This embodiment has features in that protectiveprojections are formed separately of a fork cylinder mounting member anddetachably attached to the cylinder mounting member. In the followingdescription of the second embodiment, those component parts which areidentical with the counterparts in the foregoing first embodiment aresimply designated by the same reference numerals or characters to avoidrepetitions of same explanations.

In the drawings, indicated at 31 is a cargo handling tool which isadopted in the present embodiment as a working tool in place of thecargo handling tool 21 in the first embodiment. The cargo handling tool31 is pivotally supported at the fore end of the boom 12 (the boom head16) for upward and downward turning movements. In this instance,similarly to the counterparts in the first embodiment, the cargohandling tool 31 is constituted by a frame body 22, forks 23 and boommounting plate 24, and cylinder mounting brackets 32 and protectiveprojection plates 33 which will be described hereinafter.

The cargo handling tool 31 according to the second embodiment differsfrom the cargo handling tool 21 of the first embodiment in that cylindermounting brackets 32 of different shape are employed in combination withseparable or removable protective projection plates 33 from the cylindermounting brackets 32.

Indicated at 32 are right and left cylinder mounting brackets as thecylinder mounting member which are provided on the back side of theframe body 22 between the right and left boom mounting plates 24. Thesecylinder mounting brackets 32 are adopted by the second embodiment inplace of the cylinder mounting brackets 26 in the first embodiment. Inthis instance, each one of the cylinder mounting brackets 32 is formedsubstantially in the shape of letter “L” by the use of a thick steelplate, and provided with a vertical plate section 32A which is securelyfixed to the upper and lower beams 22B and 22C of the frame body 22 atits upper and lower end portions, respectively, a foot section 32B whichis located at a lower level than the pin receiving holes 24B in the boommounting plates 24 and projected substantially horizontally toward thevehicle body 2 from the lower end of the vertical plate section 32A, anda pin receiving hole 32C which is provided in each one the foot sections32B as a cylinder connecting portion.

In this instance, the pin receiving holes 32C in the foot sections 32Bare located at a lower level and at a position closer to the vehiclebody 2 than the pin receiving holes 24B in the boom mounting plates 24.The other end of the fork cylinder 27 is pivotally connected to the pinreceiving holes 32C through a pin 29. Further, a couple of female screwsholes 32D are provided on the fore side of the pin receiving hole 32C inthe foot section 32B to receive bolts 34 which will be describedhereinafter.

Indicated at 33 are protective projection plates which are providedseparately of the cylinder mounting brackets 32. These protectiveprojection plates 33 are each formed in an arcuate shape to extend anobliquely upward direction toward the vehicle body 2 when attached to atoe portion of the foot section 32B of the cylinder mounting bracket 32in overlapped relation with the latter. A couple of bolt holes 33A areformed in a base end portion of each protective projection plate 33 atcorresponding positions relative to the female screw holes 32D of thecylinder mounting bracket 32.

By threading bolts 34 into the female screw holes 32D in the cylindermounting brackets 32 through the bolt holes 33A, the protectiveprojection plates 33 are securely fixed on the foot sections 32B of thecylinder mounting brackets 32.

Thus, for example, even when the rod 27C (the boss portion 27D) of thefork cylinder 27 is connected to the cylinder mounting brackets 32 bythe pin 29, the protective projection plates 33 alone can be attached toor detached from the cylinder mounting brackets 32 simply by tighteningor loosening the bolts 34.

Being arranged in the manner as described above, the lift truckaccording to the second embodiment provided the cargo handling tool 31has no differences from the foregoing first embodiment in a fundamentaloperating mechanism.

However, in the case of the second embodiment, the protective projectionplates 33 which are provided separately of the cylinder mountingbrackets 32 are detachably attached on the latter by the use of bolts34.

Therefore, in the event that the protective projection plate 33 isdamaged as a result of collision against an obstacle A, the damagedprotective projection plate 33 on the cylinder mounting bracket 32 canbe easily replaced by a fresh one. Accordingly, it becomes possible toprotect the rod 27C of the fork cylinder 27 over a prolonged period oftime and to enhance the operational reliability of the fork cylinder 27all the more.

Now, turn to FIGS. 8 to 11, there is shown a third embodiment of thepresent invention. This third embodiment has feature in that, inaddition to a protective projection which is provided on a cylindermounting member of a working tool, an opening is provided at a fore endof an outer boom to accommodate a cylinder mounting portion which isprovided at a fore end of an inner boom. In the following description ofthe third embodiment, those component parts which are identical with thecounterparts in the foregoing first embodiment are simply designated bythe same reference numerals or characters to avoid repetitions of sameexplanations.

In the drawings, indicated at 41 is a working mechanism which is adoptedby the third embodiment in place of the working mechanism 11 of thefirst embodiment. The working mechanism 41 is constituted by a boom 42,a boom lifting cylinder 18, a first step boom cylinder 19, a second stepboom cylinder 52, a cargo handling tool 21 and a fork cylinder 27.

Indicated at 42 is a telescopic boom which is constituted by a firststep boom 43, a second step boom 49, a third step boom 57, a boom head16 etc.

Denoted at 43 is the first step boom as an outer boom, and the firststep boom 43 is constituted by a square tubular body 44 which isextended toward front and rear direction and adapted to accommodate thesecond step boom 49 therein, and a frame body 45 which is securely fixedto the fore end of the square tubular body 44.

In this instance, as shown in FIG. 9, boom joint portion 44A forconnection to the vehicle body 2 as well as cylinder mounting portion44B are projected from the top side of a base end portion (a rear endportion) of the square tubular body 44. The boom joint portion 44A arepivotally connected to the vehicle body 2 through a pin 17. Supported onthe cylinder mounting portion 44B is a bottom side of a first step boomcylinder 19 which stretches or retracts the second step boom cylinderrelative to the first step boom 43.

On the other hand, as shown in FIG. 10, the frame body 45 is constitutedby a square flange plate 45A which is securely fixed to the fore end ofthe square tubular body 44, for example, by welding, a bottom plate 45Bwhich is securely fixed to the flange plate 45A substantially flush withbottom surface of the square tubular body 44, and right and left sideplates 45C which are located transversely face to face at the oppositesides of the bottom plate 45B and securely fixed to the bottom plate 45Band the flange plate 45A. The top side between the right and left sideplates 45C opens on the upper and lower directions. Upper ends of theright and left side plates 45C are notched downward in the forwarddirection from the respective rear sides which are fixed to the flangeplate 45A, and formed between notched upper ends 45D of the side plates45C is an opening 46 as described below.

Indicated at 46 is the above-mentioned opening which is provided at thefore end of the first step boom 43. More specifically, the opening 46 isan open space which is defined between the notched upper ends 45D of theright and left side plates 45C of the frame body 45, which is open onthe upper side. The opening 46 is open on the upward direction andprovided in a corresponding position relative to a cylinder mountingportion 50 of the second step boom 49, which will be describedhereinafter. As a result, when the second step boom 49 is contractedinto the first step boom 43 as shown in FIG. 8, the cylinder mountingportion 50A of the second step boom 49 is accommodated in the opening 46in a retracted position which is retreated rearward of the fore end ofthe first step boom 43 (of the frame body 45) toward the base end(toward the square tubular body 44).

Indicated at 47 are lower slide pads which are attached on the bottomplate 45B of the frame body 45 for sliding contact with the lower sideof the second step boom 49 which is accommodated in the first step boom43. Designated at 48 are side slide pads which are attached on the rightand left side plates 45C of the frame body 45 for sliding contact withright and left side surfaces of the second step boom 49, respectively.

Indicated at 49 is the above-mentioned second step boom as the innerboom which is telescopically received in the first step boom 43. Asshown in FIG. 9, this second step boom 49 is constituted by a squaretubular body 50 which is square in sectional shape and extended towardfore and rear ends of the vehicle and adapted to accommodate the thirdstep boom 57 therein, and a frame body 51 which is securely fixed to thefore end of the square tubular body 50.

In this instance, cylinder mounting portion 50A are provided on theupper side of a fore end portion of the square tubular body 50 tosupport thereon the rod side of the first step boom cylinder 19. Asshown in FIGS. 8 and 9, when the second step boom 49 is contracted intothe first step boom 43, the cylinder mounting portion 50A isaccommodated in the opening 46 in the frame body 45 of the first stepboom 43. Further, cylinder mounting portion 50B are provided in the baseend side of the square tubular body 50 to support the bottom side of thesecond step boom cylinder 52, which expands or contracts the third stepboom 57 relative to the second step boom 49.

On the other hand, as shown in FIG. 9, the frame body 51 is constitutedby a flange plate 51A in the form of a square frame which is securelyfixed to the fore end of the square tubular body 50 by welding or othersuitable means, a bottom plate 51B securely fixed to the flange plate51A substantially flush with the bottom surface of the square tubularbody 50, and right and left side plates 51C (of which only the rightside plate is shown in the drawings) which are securely fixed to thebottom plate 51B and the flange plate 51A and faced toward each otheracross the bottom plate 51B.

In this instance, lower and upper slide pads 53 and 54 are attached onthe lower side and upper side of a base end portion of the squaretubular body 50, respectively, for sliding engagement with inner surfaceof the square tubular body 44 of the first step boom 43.

Further, lower slide pads 55 are attached on the bottom plate 51B of theframe body 51. These lower slide pads 55 are brought into slidingcontact with the lower side of the third step boom 57 when the latter isaccommodated into the second step boom 49. Furthermore, side slide pads56 are attached on the side plates 51C of the frame body 51 for slidingengagement with right and left lateral sides of the third step boom 57.

Denoted at 57 is the above-mentioned third step boom which istelescopically received in the second step boom 49. This third step boom57 is constituted by a square tubular member which is square insectional shape and extended forward and rearward of the vehicle body.Cylinder mounting portion 57A are provided internally of the third stepboom 57 to support the rod side of the second step boom cylinder 52. Theboom head 16 is securely fixed to the fore end of the third step boom57, and the cargo handling tool 21 is pivotally supported at the foreend of the boom head 16.

In this instance, lower and upper slide pads 58 and 59 are attached onthe lower and upper sides of a base end portion of the third step boom57, respectively, for sliding engagement with inner surfaces of thesquare tubular body 50 of the second step boom 49.

The lift truck according to the third embodiment of the presentinvention is provided with the working mechanism 41 which is arranged inthe manner as described above, having the protective projections 26Dprovided on the cylinder mounting brackets 26 of the cargo handling tool21 for protection of the rod 27C of the fork cylinder 27 from obstaclesof the ground. In this regard, there is no difference in particular fromthe working mechanism 11 of the first embodiment.

However, in the case of the working mechanism 41 according to the thirdembodiment, the opening 46 which opens on the upper side is provided onthe frame body 45 at the fore end of the first step boom 43, at acorresponding position relative to the cylinder mounting portion 50Awhich is provided on a fore end portion of the second step boom 49.Consequently, when the second step boom 49 is contracted into the firststep boom 43 as shown in FIG. 8, the cylinder mounting portion 50A canbe accommodated in the opening 46 of the frame body 45, that is to say,in a retracted position which is receded toward the base end of thefirst step boom 43 (toward the square tubular body 44).

As a result, the second step boom 49 can be contracted more deeply intothe first step boom 43 to minimize the distance L between the fore endsof the first step and second step booms 43 and 49. This means that, whenthe second step boom 49 is fully contracted, the entire boom 42 can befolded into a smaller length to ensure safer travels of the lift truck.

On the other hand, according to the third embodiment of the invention,the lower slide pads 47 are provided on the bottom plate 45B of theframe body 45 of the first step boom 43 for sliding contact with thelower side of the second step boom 49. Therefore, when the second stepboom 49 is extended out of the first step boom 43 as shown in FIG. 11, awider spacing S can be secured between the lower slide pads 47 and theupper slide pads 54 which are provided on the top side of a base endportion of the second step boom.

Now, turning to FIGS. 12 and 13, there is shown a fourth embodiment ofthe present invention. This embodiment has features in that a boommounting member and a cylinder mounting member are provided as integralparts of mounting plates which are attached to the back side of aworking tool, and protective projections which are provided on themounting plates. In the following description of the fourth embodiment,those component parts which are identical with the counterparts in theforegoing first embodiment are simply designated by the same referencenumerals or characters to avoid repetitions of same explanations.

In the drawings, indicated at 61 is a cargo handling tool which isadopted in the present embodiment in place of the cargo handling tool 21in the first embodiment. This cargo handling tool 61 is pivotallysupported at the fore end of the boom 12 (boom head 16) for upward anddownward turning movements. The cargo handling tool 61 is constituted bya frame body 62, fork 63 and mounting plates 64.

Indicated at 62 is a rectangular frame body providing a base for thecargo handling tool 61. This frame body 62 is largely constituted byright and left side plates 62A, an upper beam 62B, a lower beam 62C, andan intermediate beam 62D.

Denoted at 63 are L-shaped forks which are attached to the front side ofthe frame body 62. More specifically, these forks 63 are securely fixedto the intermediate beam 62D of the frame body 62 at the respectiveupper ends, and lower end portions of the forks 63 are projected forwardfrom the lower beam 62C to provide cargo loading surfaces 63A.

Designated at 64 are right and left mounting plates which are providedon the back side of the frame body 62. Each one of these mounting plates64 is formed in such a way as to integrate a boom mounting member and acylinder mounting member into one structure, and thus has functions of aboom mounting member and functions of a cylinder mounting member aswell. In this instance, each mounting plate 64 is formed substantiallyin the shape of letter “J” by the use of a thick steel plate material,and provided with a vertical plate section 64A which is securely fixedto the upper beam 62B and the lower beam 62C at its upper and lowerends, respectively, and a foot portion 64B which is projectedsubstantially horizontally from the lower end of the vertical plateportion 64A toward the vehicle body.

A pin receiving hole 64C is provided in the base end side of the footportion 64B for connection to the boom. In addition, for connection to acylinder, another pin receiving hole 64D is provided in a fore end sideof the foot portion 64B (on the side of the vehicle body). Further,integrally formed at a toe portion of the foot portion 64B is aprotective projection 64E which will be described in greater detailhereinafter.

In this instance, the pin receiving holes 64C and 64D are bored side byside in the horizontal direction. That is to say, when the cargo loadingsurfaces 63A of the forks 63 are in a horizontal state relative to theground surface, the centers of the pin receiving holes 64C and 64D areat the same height from the ground surface.

After placing the foot portion 64B of the two mounting plates 64 to gripthe boss portion 16D of the boom head 16 from opposite sides, the pin 25is inserted in the boss portion 16D and the pin receiving holes 64C inthe two mounting plates 64. Whereupon, the cargo handling tool 61 isattached to the fore end of the boom head 16 pivotally for upward anddownward turning movements about the pin 25. Upon inserting the pin 29into the pin receiving holes 64D in the mounting plates 64 and the bossportion 27D, the rod 27C of the fork cylinder 27 is pivotally connectedto the cargo handling tool 61 for turning movements about the pin 29.

Indicated at 64E are protective projections which are provided on theright and left mounting plates 64. Each one of the protectiveprojections 64E is integrally formed at the toe end of the foot portion64B of each mounting plate 64 immediately on the outer side of the pinreceiving hole 64D. In this instance, the two protective projections 64Ewhich are positioned on the opposite sides of a fore end portion of thefork cylinder rod 27C are bent obliquely upward to the fork cylinder 27and are projected toward the vehicle body to protect the rod 27C of thefork cylinder 27 from obstacles on the ground.

With the cargo handling tool 61 which is arranged as described above,the lift truck according to the fourth embodiment has no differencesfrom the foregoing first embodiment in fundamental performance.

However, in the case of the fourth embodiment, right and left mountingplates 64 which are attached to the back side of the frame body 62 ofthe cargo handling tool 61 are of a complex form, each integrallycontaining a boom mounting member and a cylinder mounting member. As aconsequence, the cargo handling tool 61 can be simplified inconstruction as compared with the cargo handling tool which has boommounting members and cylinder mounting members separately attached tothe back side of the frame body 62.

In the above-described first embodiment, the protective projections 26Dwhich are provided on the cylinder mounting brackets 26 are exemplifiedas arcuate projections which are bent toward the fork cylinder 27arcuately about the pin 25, which connects the boom mounting plates 24of the cargo handling tool 21 with the boom head 16. However, it is tobe understood that the present invention is not limited to theparticular form shown. For example, as in a modification shown in FIG.14, there may be employed protective projections 26D′ which are arrangedto project rectilinearly in an obliquely upward direction toward thefork cylinder 27 from the pin receiving holes 26C to the cylindermounting brackets 26.

Further, in the above-described first embodiment, one fork cylinder 27is provided between the cargo handling tool 21 and the boom 12, and therod 27C of the fork cylinder 27 is protected by the protectiveprojections 26D which are provided on the cylinder mounting brackets 26of the cargo handling tool 21. However, in this regard, the presentinvention is not limited to the particular arrangements shown. Forexample, in a case where a plural number of fork cylinders are providedbetween the boom 12 and a cargo handling tool 21, the protectiveprojections can be provided for each one of the rod of the forkcylinders in a similar manner. The same applies to the secondembodiment.

Furthermore, in each one of the foregoing embodiments of the invention,by way of example the bottom side of the tube 27A of the fork cylinder27 is mounted on the brackets 16E on the part of the boom head 16, whilethe rod 27C (the boss portion 27D) of the fork cylinder 27 is supportedon the cylinder mounting brackets 26 on the part of the cargo handlingtool 21, protecting the rod 27C by the protective projections 26D whichare provided on the cylinder mounting brackets 26. However, the presentinvention is not limited to the particular examples shown. For instance,it is also possible to support the rod 27C of the fork cylinder 27 bythe brackets 16E on the part of the boom head 16, while supporting thebottom side of the tube 27A by the cylinder mounting brackets 26 on thepart of the cargo handling tool 21. In this case, the tube 27A isprotected by the protective projections 26D on the cylinder mountingbrackets 26 from possibilities of deformations and damages which mightotherwise occur to the tube 27A as a result of collision againstobstacles.

Moreover, in the foregoing first and second embodiments, the boom 12 isexemplified as the three stepstyle booms which are constituted by thefirst step boom 13, the second step boom 14 and third step boom 15.Needless to say, the present invention is not limited to booms of thattype, and can be similarly applied to single step type booms or othermulti-step type booms operating in two steps or more than four steps.

Furthermore, in each one of the foregoing embodiments, by way of examplethe present invention has been described in connection with a lift truckwhich is equipped with the cargo handling tool 21 (31) for lifting andtransferring freight goods. However, the present invention is notlimited to the lift trucks of the type shown but can be widely appliedto other automotive working machines, for example, to wheel loaderswhich are equipped with a loader bucket as a working tool.

1. An automotive working machine having an automotive vehicle bodyprovided on left and right front wheels and left and right rear wheels,a boom liftably mounted on said vehicle body, a working tool rotatablysupported on a fore end portion of said boom, and a tool operatingcylinder located between said boom and said working tool at one and theother axial end thereof to turn said working tool in upward and downwarddirections relative to said boom, characterized in that said automotiveworking machine comprises: a boom mounting member provided on the backside of said working tool, on the side of said vehicle body, and havinga boom connecting portion pivotally connected to said fore end portionof said boom, along with a cylinder mounting member having a cylinderconnecting portion pivotally connected to the other end of said tooloperating cylinder; and protective projections provided on said cylindermounting member and projected from the back side of said working tooltoward said vehicle body to protect said other end of said tooloperating cylinder from obstacles on a ground surface when said vehiclebody is put in travel with said boom in a folded position on the side ofthe ground; wherein said protective projections are bent in an obliquelyupward direction from a cylinder connecting portion of said cylindermounting member toward said tool operating cylinder.
 2. An automotiveworking machine as defined in claim 1, wherein said protectiveprojections are each in the form of an arcuate projection extendingtoward said tool operating cylinder and bent arcuately about a boomconnecting portion of said boom mounting member at the back of saidworking tool.
 3. An automotive working machine as defined in claim 1,wherein said protective projections are formed separately from saidcylinder mounting member and detachably attached to said cylindermounting member.
 4. An automotive working machine as defined in claim 1,wherein said protective projections are constituted by a pair of rightand left plate-like members adapted to grip the other end of said tooloperating cylinder therebetween.
 5. An automotive working machine asdefined in claim 1, wherein said tool operating cylinder is constitutedby a tube having one axial end thereof connected to said boom, a pistonslidably fitted in said tube, and a rod having one axial end thereofconnected to said piston and projected out of said tube at the otheraxial end to connect to the cylinder connecting portion of said cylindermounting member; said protective projections being adapted to protectthe other projected end of said rod.
 6. An automotive working machine asdefined in claim 1, wherein said boom is provided with an outer boom ofhollow tubular shape being liftably connected to said vehicle body at abase end portion, and an inner boom being extensibly fitted in saidouter boom and provided with a cylinder mounting portion on a fore endportion thereof; a boom cylinder being located outside of said outerboom and having a base end portion thereof attached to said outer boomand a fore end portion supported on said cylinder mounting portion onsaid inner boom; and said outer boom being provided with an opening in afore end portion to accommodate said cylinder mounting portion in aretracted position inward of a fore end of said outer boom when saidinner boom is retracted into said outer boom.
 7. An automotive workingmachine as defined in claim 6, wherein said outer boom is composed of atubular body for accommodating said inner boom, and a box-like framebody securely attached to a fore end of said tubular body, said framebody defining therein said opening in a corresponding position relativeto said cylinder mounting portion of said inner boom.